Things worth knowing about hot tubs

What's in the water? Before you lower yourself into that steamy hot tub, think twice about what's living under the surface.

1. Hot tub "folliculitis" is an infection of the hair follicles that results from exposure to certain bacteria that live in warm, wet areas, according to the Centers for Disease Control and Prevention. Pseudomonas appears as itchy bumps, sometimes filled with pus. It may then develop into dark red, tender nodules. The disease usually clears on its own.

2. Hot tub lung: Indoor hot tub users are vulnerable to a respiratory illness from inhaling mycobacteria, which can grow in tubs that aren't cleaned often, according to the Mayo Clinic. Symptoms include a flulike fever and chills, shortness of breath, a dry cough, night sweats and weight loss. Treatment may include antibiotics and prednisone; some sufferers have been hospitalized.

3. Wannabe fathers beware: Male fertility plunges with frequent dips into a hot tub, according to a 2007 University of California-San Francisco study.

4. Help for diabetes? There can be benefits. Hot tub therapy helped a group of people with Type 2 diabetes reduce their blood sugars, lose weight and improve sleep patterns in a 1999 pilot study that appeared in The New England Journal of Medicine. The participants sat in a hot tub with water as hot as 104 degrees for 30 minutes per day, six days per week, for three weeks. Researchers caution that diabetics shouldn't try this without a doctor's approval.

5. Hydrotherapy: Along with treating common ailments such as back and joint pain, hot tub therapy has been used to treat high blood pressure. Patients are always advised to consult their doctor before trying this therapy because, initially, the therapy raises blood pressure due to increased body temperature. Hot water dilates blood vessels, and the heart does not have to work hard in pumping blood, providing relief. Whirlpools used in hospitals and medical clinics are safest.